In an information processing system, it is continuously required to reduce power consumption. For example, in recent years, with the spread of the cloud computing, an aggregation of a server device and a storage device into a data center is in progress. In such a data center, since a short-term improvement of a power facility and an air-conditioning facility is difficult, a demand for power saving of the server device or the storage device increases.
Regarding the technology for reducing the power consumption, the following proposals are made. For example, there has been proposed a drive device that transitions to any one of low power consumption modes each having different power consumption levels according to an operating environment and an operating condition of a host computer. Further, for example, a control method is proposed in which a standby disk included in a disk array device is periodically activated to check an operation, and when it is confirmed that the standby disk is in a normal condition, the standby disk is stopped and put in a standby state.
Meanwhile, as a method for improving a fault tolerance of the information processing system, a method is known in which an information processing apparatus is made redundant such that when one information processing apparatus is activated, the other information processing apparatus is put in a standby state, and when a fault occurs in the information processing apparatus in activation, the information processing apparatus in the standby state is activated to take over the processing.
Related technologies are disclosed in, for example, Japanese Laid-Open Patent Publication No. 2006-031537 and Japanese Laid-Open Patent Publication No. 06-089146.